Exciton-Induced Aggregation in Novel Guest Emitters for wet-coated OLEDs

The promise of low-cost fabrication via “wet” processes, such as inkjet printing, in manufacturing flat panel displays and solid-state lighting has long been one of the main motivations behind the pursuit of Organic Light-Emitting Devices (OLEDs). The vast majority of OLEDs in commercial products are still fabricated by costly “dry” vacuum-deposition methods however. A primary reason is the significantly lower electroluminescence (EL) stability of devices made by wet-coating in comparison to their vacuum-deposited counterparts. Recent work at the University of Waterloo (UW) has revealed that the stability gap is caused by molecular aggregation driven by exciton-polaron interactions during electrical stress; a previously unknown phenomenon that is now understood to play a major role in OLED EL loss over time and to affect wet-coated materials more readily. More recent work has shown that the phenomenon affects the guest emitters in OLED host-guest systems highlighting the necessity of adopting new molecular architectures and design strategies in developing these materials. The goal of the project is to develop and fabricate optimized OLED architectures for testing these novel emitters and using electrical electroluminescence and photoluminescence measurements to study and compare their photophysical and electroluminescence properties and their dependence on the fabrication method.

Fatemeh Samaeifar
Faculty Supervisor: 
Hany Aziz
Partner University: